51720118655 has 4 divisors (see below), whose sum is σ = 62064142392. Its totient is φ = 41376094920.

The previous prime is 51720118573. The next prime is 51720118661. The reversal of 51720118655 is 55681102715.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 51720118655 - 2⁸ = 51720118399 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5172011861 + ... + 5172011870.

It is an arithmetic number, because the mean of its divisors is an integer number (15516035598).

Almost surely, 2^51720118655 is an apocalyptic number.

51720118655 is a deficient number, since it is larger than the sum of its proper divisors (10344023737).

51720118655 is a wasteful number, since it uses less digits than its factorization.

51720118655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10344023736.

The product of its (nonzero) digits is 84000, while the sum is 41.

The spelling of 51720118655 in words is "fifty-one billion, seven hundred twenty million, one hundred eighteen thousand, six hundred fifty-five".